1. Field of the Invention
This invention relates to wire and cable. In one aspect the invention relates to flexible wire and cable coverings while in another aspect, the invention relates to olefin multiblock copolymer (OBC) compositions from which flexible wire and cable coverings are made. In yet another aspect the invention relates to the use of high comonomer content olefin multiblock copolymers in the compositions from which flexible wire and cable coverings are made.
2. Description of the Related Art
Olefin multiblock copolymers (OBC) will produce semiconductive compositions with more stable electrical conductivity as compared to homogeneously branched polyolefin elastomers commonly used today. For example, significant electrical conductivity and stability differences exist between representative resins from the two classes of polymers with similar melt indices (MI) and density, namely ENGAGE™ 7447 ethylene-butene homogeneously branched copolymer (0.865 g/cc density, 5 MI) or ENGAGE™ 8200 ethylene-octene homogeneously branched copolymer (0.870 g/cc density, 5 MI), and INFUSE® 9507 olefin multiblock ethylene-octene copolymer (0.865 g/cc density, 5 MI). Of continuing interest is a semiconductive composition exhibiting a low volume resistivity (<500 ohm-cm) and high performance with improved mechanical properties that is also easy to process.